Nigeria, reeling from the oil price plunge that has slashed vital revenues, has asked the African Development Bank for a $1 billion loan to help fund an increased budget deficit, the AFDB said on Tuesday.

The bank said it was considering the loan to Africa's largest economy and oil producer, where the drop in crude prices has hit growth, and that an appraisal mission would visit soon to work with authorities.

Nigeria is planning to borrow as much as $5 billion to help fund a deficit due to the slump in global oil prices, which have also sent its naira currency into a tailspin.

Finance Minister Kemi Adeosun said this week Nigeria had held exploratory talks with the World Bank and looked at options to borrow from the AFDB and China Exim Bank.

Earlier this month she said that about $4 billion might come from international institutions and the remainder from eurobonds.